System and method for receive diversity combining

ABSTRACT

Receive diversity combining uses signals received at multiple antennas and combine them to obtain a higher overall signal to noise ratio. Multi-level ranking is employed to determine the weight assigned to each channel and, once the channels are weighted the weighted signals are added together. In a two-level example the first level ranks the signals according to fidelity of the signal. This is done by calculating cross correlation coefficients, where highest coefficient indicates best fidelity. The second level ranks the channels according to peak to average power ratio. The lowest value indicates the best channel. The two rankings are combined to generate the weight coefficient for each channel prior to combining the signals from all the channels.

RELATED APPLICATION

This disclosure relates to and claims priority benefit from U.S.Provisional Application No. 62/874,447, filed on Jul. 15, 2019, thedisclosure of which is incorporated herein by reference in its entirety.

BACKGROUND 1. Field

This disclosure relates generally to the field of wirelesscommunication, e.g., satellite-based communication and microwave pointto point communication, and to the control of multiple phased arrayantennas communicating with multiple antennas.

2. Related Art

Satellite-based communication is a common way for ships, planes, trains,and people to connect into the global Internet. The method of connectionvaries from simple connectivity in low frequencies to complex andexpensive connectivity in higher frequencies.

The complexity is mostly associated with the antenna. Higher frequenciescommunication requires utilizing an antenna which points at thesatellite. Sometimes the user is moving and the satellite is relativelyfixed to earth, but the antenna must maintain pointing to the satellite.There are cases where the satellite is moving and the antenna must stillmaintain its pointing direction to the satellite. In either case, aself-steering antenna which can maintain its directional steering is animportant benefit. The inverse is also true—in many cases the satelliteitself needs to steer the beam to a particular point on the earth.Either way there is a transmitter and a receiver, and one of the two, orboth of them may need to steer their beams to make their respectiveconnections.

Self-steering antenna systems come in two forms. They are eitherMechanically Steered Antenna's (MSA's) which utilize some form of eitherparabolic dish, array of patches or other planar and 3D antenna designsin conjunction with a motor assembly to steer either directly or throughsome sort of an amplifying lens towards the receiver, or, alternativelythere are Electronically Steered Arrays (ESA's) which use a variety offormats to electronically steer a beam with no moving parts, such as byphase shifting of phased array antennas.

A common way to describe the capabilities of a component like an antennasystem is SWaP-C+R, which stands for Size, Weight, Power, Cost andReliability. These are some of the key determinations of whether anantenna system is fit for a particular purpose. As each of the variablesincreases, the number of applicable use cases of the antenna is reduced.For instance, a train needs a low profile antenna so that it may gothrough tunnels, and a plane needs a low profile antenna so as tominimize drag and reduce vortices which impact its flightcharacteristics. The MSA's have the disadvantage of being physicallylarge in the z-dimension, and also have moving parts subject to wearover time and therefore reduced reliability. The ESA's typically had thedisadvantage of consuming significant amounts of power, being heavybecause of the heat sinks or other heat dissipation solutions associatedwith that power, and while physically smaller than an MSA, they havestill been quite thick and ultimately expensive. However ESA's typicallyhave a smaller size than an MSA and a higher reliability, thus forcertain use cases they have been preferred.

Another important variable in antenna design is aperture size. Theaperture size represents the effective collecting surface area of theantenna. This is usually some form of x and y coordinates, representingthe surface area presented to the transmitting satellite. The mostdesired antenna would have a large aperture (x and y) always facing thetransmission origin and no z (height/thickness). The larger thisaperture size, the higher the gain of the receiving or transmittingsignal and therefore the spectral efficiency of the overall system goesup, i.e., for less bandwidth we would get a higher data rate, whichtranslates directly to a significant advantage in the market. Moreover,the higher the gain the less likely the transmitted beam will place itspower in unintended directions and cause interference since higher gainequals a narrower beam. Moreover the narrow beam of a higher gainantenna makes it less likely the antenna will receive such unintendedinterference. From the signal strength perspective, a larger x/y surfacearea—aperture—is desired, which in turn also reduces the needed poweramplifier level for a given link, i.e. less power that needs to beprovided to the antenna.

A challenge with the aforementioned technologies is that the largeSWaP-C+R has limited the applications for antenna systems. The mostefficient beam is the one directly in front of the antenna itself whichis called boresight. The boresight is straight above the middle of theantenna i.e. orthogonal to the radiating surface of the antenna. An MSAcan turn the entire antenna so it maintains boresight towards asatellite, thereby preserving the aperture size presented to thesatellite. Conversely, an ESA tilts the beam electronically, thuspresenting a smaller aperture as seen from the satellite, thus degradingits performance by 2 or 4 times depending on the off-angle axis betweenthe receiving and transmitting side. The technical reduction in sizefollows the 10*log 10 cos θ scan loss which directly relates to the seenarea i.e. aperture dimension seen from a steered direction. While theMSA will have no scan loss, it requires a large ‘swept volume’ in orderto maintain its pointing direction. This increases both size and weight.In some cases antennas will combine both ESA's and MSA's into a singleantenna using an ESA for one direction, perhaps azimuth and a mechanicalsteering assembly in the elevation direction. These represent a balancein SWaP-C+R for the application.

Another problem with the current antenna systems is that their physicalsize often limits them to only a single receive and transmit antennaassembly per application. For example, aircraft need steerable antennasin order to maintain a connection with the satellite. However, theSWaP-C limits the number of steerable antennas to a single antenna.Consequently, when the airplane turns by tilting, the connection to thesatellite is lost.

In many cases there is also a need for the terminal to connect tomultiple satellites at the same time. Moreover, as each satellite mayrequire a particular modem with its particular waveform, there may alsobe a need to switch the modem/antenna combination as needed.

Accordingly, a need exists in the art for improved satellitecommunication.

SUMMARY

The following summary of the disclosure is included in order to providea basic understanding of some aspects and features of the invention.This summary is not an extensive overview of the invention and as suchit is not intended to particularly identify key or critical elements ofthe invention or to delineate the scope of the invention. Its solepurpose is to present some concepts of the invention in a simplifiedform as a prelude to the more detailed description that is presentedbelow.

Embodiments disclosed herein enable multiplexing multiple antennas andmodems to enable configuring different modem/antenna combinations, thusgenerating transmission paths on the fly.

Disclosed embodiments provide an improved control of communication pathsamong communication devices and satellites. In disclosed embodimentsdifferent paths are configured in real time based upon parameters suchas the available satellites, the strength of the signal received fromeach available satellite, the amount and type of data to be transmitted,the cost for transmission in each path, the user account permissions toutilize any of the available paths based on the user's subscription,etc.

Disclosed embodiments enable real time control of communication betweena moving platform and a satellite, enabling maintaining communicationchannels regardless of the movement of the platform, e.g., and airplaneor a ship. The platform may have multiple phased array antennas, eachhaving boresight pointing at different direction with respect to theplatform (e.g., up, left, right, etc.). As the platform moves, e.g.,turns, a controller determines the best antenna(s) to use for thetransmission and can select and deselect antennas in real time such thatthe antenna having the best RSSI (Received Signal Strength Intensity) isalways selected.

In disclosed embodiments a lower SWaP-C form of ESA is employed by usingmultiple ESAs, e.g., using a variable dielectric technology as phaseshifters for the ESAs. Utilizing a variable dielectric enables newmethods of connectivity for either satellites or ground antenna systemsand these new forms of connectivity are particularly beneficial forembodiments disclosed herein.

For security purposes encryption of data is often used, howeverencryption has limitations in the face of quantum computing. Thereforedisclosed embodiments utilize multiple satellites to split data acrossat least one satellite and multiple other paths and recombine this datain a secure location. Consequently, any interception of an individualpath will render only a fraction of the encrypted data file. Thusdisclosed aspects provide a more secure file transfer mechanism.

In other cases there is a need to utilize multiple ESA's such that whena platform, such as a train or plane, moves and turns, the mostboresight facing ESA will be selected for the highest efficiency. Such amechanism to automatically switch between ESA's is provided byembodiments disclosed herein.

In still other cases there is rapid transition and blockage of themultiple ESA's, or the aperture size may need to be small and multipleESA's must be placed in available and potentially at odd angles relativeto each other and the distance between the ESA's may be significant. Amethod of utilizing very low SWaP-C ESA's and dynamically combining thesignal strength of multiple of these ESA's and potentially dynamicallychanging the modems associated with such varying combinations of ESA'sis also provided by disclosed embodiments. By dynamically it means thatthe various connections are managed in real time, such that at anyinstance each connection may be replaced or deleted, or a new connectionadded, as merited by the transmission/reception circumstances.

In still other cases where there are multiple ESA's one may also includea baseband solution to provide some MIMO, nulling or other basebandcapabilities, either digital or analog, to improve data rates.

In disclosed embodiments an antenna system for satellite communicationis provided, comprising: a plurality of antennas, each antennacomprising a phased array of radiators; a plurality of modems; a switchconfigured for dynamically coupling any antenna to any of the modems; aplurality of communication devices; a router configured to dynamicallycouple any of the communication devices to any of the modems; and acontroller controlling the switch and the router to provide real timeinstructions to configured connections of the plurality of antennas, themodems and the communication devices.

In general aspects, a system is mounted onto a mobile platform forcommunication with satellites, and comprises: a plurality of phasedarray antennas, each having a plurality of radiators and a plurality ofphase shifters, each phase shifter introducing delay to an RF signalpropagating therethrough; at least one phase controller operating thephase shifters to introduce the delay to the RF signal; a plurality ofmodulators/demodulators; a switch operatively connecting any of themodulators/demodulators to any of the phased array antennas asdetermined in real time; a communication device; a router operativelyrouting signals between any of the modulators/demodulators and thecommunication device; and, a control circuit providing real timeinstructions to the switch to form connections between themodulators/demodulators to any of the phased array antennas and to therouter to route signals between the modulators/demodulators and any ofthe phased array antennas.

In general aspects, a method is provided for controlling communicationof a plurality of phased array antennas and a plurality of satellites,comprising: receiving an indication of data to be transmitted from acomputing device to a satellite; determining available satellites forcommunication; directing the phased array antennas to steer towards aselected satellite; receiving received signal strength intensity (RSSI)signal from each phased array antenna; based on the RSSI signalselecting a phased array antenna for transmission; connecting the phasedarray antenna for transmission to a selected modulator; operating arouter to connect the modulator to the computing device; and initiatingtransmission of the data to be transmitted.

In further aspects, a method for combining a transmission signalsreceived at a plurality of antennas is disclosed, comprising:calculating a cross correlation coefficient for signals obtained fromeach of the plurality of antennas; selecting the signal generating thehighest coefficient as a golden reference signal; using the goldenreference signal to time-synchronize the transmission signals receivedat a plurality of antennas; deriving peak power to average power ratiofor each of the transmission signals received at a plurality ofantennas; using the cross correlation coefficients and the peak power toaverage power ratio to generate a weighting coefficient for each of thetransmission signals received at a plurality of antennas; applying theweighting coefficient to each of the transmission signals received at aplurality of antennas to generate a plurality of weighted signals; andsumming the plurality of weighted signals. As noted, the method mayfurther include using the golden reference signal to calibrate the phaseof the transmission signals received at a plurality of antennas.

According to other aspects, a system is provided for receiving atransmission signal, comprising: a plurality of antennas, each antennareceiving a received signal; a ranking module ranking the plurality ofantennas according to quality of the received signal of each of theplurality of antennas and generating a corresponding level one signal,and selecting highest ranking antenna as a golden reference signal; asynchronizer using the golden reference signal to synchronize thereceived signals of all of the plurality of antennas; a level two modulecalculating peak to average power ratio for each of the received signalof each of the plurality of antennas and generating a correspondinglevel two signal; a scoring unit generating a weighting score for eachof the received signal of each of the plurality of antennas using thelevel one and level two signals; a weighting module applying theweighting score to each corresponding received signal of each of theplurality of antennas to generate a plurality of weighted signals; and,a summing module combining all of the weighted signals.

Disclosed aspects include a method for combining received signals from aplurality of antennas, comprising: for each of the antennas generating aranking score indicative of trust worthiness of the received signal; foreach of the antennas generating a quality score indicative of the peakto average power ratio (PAPR) of the received signal; for each of theantennas using the corresponding ranking score and quality score togenerate a weight; for each of the antennas applying the weight to thereceived signal to generate weighted signal; and, summing all weightedsignals from the plurality of antennas to generate a weighted combinedsignal. Generating a ranking score may comprise calculating crosscorrelation coefficient and may further comprise calculating correlationsum CSn for each antenna. The method may further comprise assigningreceived signal having highest ranking score as reference signal andtime-aligning all received signals to the reference signal andcalibrating phase of all received signals to the reference signal.Generating the quality score may comprise calculating the PAPR using anumerator value which is below 100% of maximum amplitude squared.

Also, disclosed aspects involve a method for combining received signalsfrom a plurality of antennas, comprising: calculating a crosscorrelation coefficient for the received signals obtained from each ofthe plurality of antennas; selecting a signal generating the highestcoefficient as a golden reference signal; using the golden referencesignal to time-synchronize the received signals; deriving peak power toaverage power ratio (PAPR) for each of the received signals; using thecross correlation coefficients and the peak power to average power ratioto generate a weighting coefficient for each of the received signals;applying the weighting coefficient to each of the received signals togenerate a plurality of weighted signals; and, summing the plurality ofweighted signals.

Additionally, disclosed aspects include a system for combining receivedsignals from a plurality of antennas, comprising: a signal digitizerreceiving the received signals and generating digitized signals; a firstranking module ranking the digitized signals by comparing each ofdigitized signal's correlation with the rest of the digitized signalsand selecting highest ranked digitized signal as a reference signal; asecond ranking module calculating a peak to average power ratio (PAPR)for each digitized signal; a weighting module receiving the ranking fromthe first ranking module and the PAPR from the second ranking module andgenerating an assigned weight for each of the digitized signals; aweight applicator applying the assigned weight to each of the digitizedsignals to generate weighted signals; and a summing module summing theweighted signals. The system may further comprise a time synchronizersynchronizing the digital signals according to the reference signal. Thesystem may further comprise a phase calibration module calibrating thedigital signals according to the reference signal. The first rankingmodule may comprise a cross-correlation calculating module and may alsoinclude a correlation sum module summing cross-correlation coefficientscalculated by the cross-correlation calculating module.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, exemplify the embodiments of the presentinvention and, together with the description, serve to explain andillustrate principles of the invention. The drawings are intended toillustrate major features of the exemplary embodiments in a diagrammaticmanner. The drawings are not intended to depict every feature of actualembodiments nor relative dimensions of the depicted elements, and arenot drawn to scale.

One or more embodiments of the present invention are illustrated by wayof example and not limitation in the figures of the accompanyingdrawings, in which like references indicate similar elements and inwhich:

FIG. 1 illustrates an antenna array according to an embodiment, having acontroller for individually controlling each phase shifter therebysteering the main beam.

FIGS. 2 and 2A illustrate embodiments for deployment of multiple phasedarray antennas for communication with one or more satellites.

FIGS. 3-3B illustrates embodiments utilizing fiber optics for fast andefficient management of the multiple signals.

FIG. 4 illustrates an example of generating path diversity which isbeneficial especially for secure transmission of files or for loadbalancing.

FIG. 5 illustrates a flow chart for steps that may be employed in atransmit process, while FIG. 5A illustrates steps that may be employedin a receive process according to embodiments.

FIG. 6 illustrates an architecture of employing multiple antennas forreceive diversity combining method according to an embodiment.

FIG. 7 illustrates structure of the channels in a receive diversitycombining architecture according to an embodiment.

FIG. 8 illustrates architecture of digital signal processing for receivediversity combining according to an embodiment.

DETAILED DESCRIPTION

Embodiments of the inventive real-time multiplexing antennas and controlwill now be described with reference to the drawings. Differentembodiments or their combinations may be used for different applicationsor to achieve different benefits. Depending on the outcome sought to beachieved, different features disclosed herein may be utilized partiallyor to their fullest, alone or in combination with other features,balancing advantages with requirements and constraints. Therefore,certain benefits will be highlighted with reference to differentembodiments, but are not limited to the disclosed embodiments. That is,the features disclosed herein are not limited to the embodiment withinwhich they are described, but may be “mixed and matched” with otherfeatures and incorporated in other embodiments.

Incidentally, references made herein to a satellite, a platform, or aterminal are interchangeable and are only for illustration purposes. Thephysical locations may be swapped such that the steerable beam and itseffects may originate on the satellite, the platform, terminal or all.The same is true for the receiving and transmitting—either side may bethe receiving or the transmitting side and the use of the words eitherreceiver or transmitter are for illustration only and not meant to limitthe inverse or even simultaneous receive and transmit.

In many types of RF antennas, reception and transmission aresymmetrically reciprocal such that a description of one equally appliesto the other. In this description it may be easier to explaintransmission, but reception would be the same, just in the oppositedirection. Also, in the disclosed embodiments it is assumed that thedisclosed antenna is mounted or integrated onto a platform, and its mainbeam is aimed at another antenna, herein sometimes referred to as thetarget. The antenna of the target is also mounted or integrated onto aplatform, and either or both platforms may be moving. For example, theantenna may be mounted on a vehicle, such as an airplane, a ship, anautomobile, etc., and the target may be mounted on, e.g., a satellite.The symmetry concept applies here as well, as the antenna may be the onethat is mounted on the satellite, while the target may be mounted on avehicle.

FIG. 1 illustrates a phased array antenna, also referred to aselectronically steerable or scanned array, which may be used in any ofthe embodiments disclosed herein. A phased array refers to an array ofradiators forming a main beam, wherein the direction of the main beam iselectronically steerable by changing the phase/time delay of the RFenergy arriving at each of the radiators. For simplicity, theillustration shows a linear array, but for the disclosed embodiments itis more beneficial to utilize a two-dimensional array, such that thebeam can be steered in two dimensions. The array comprises radiatingelements 105, each connected to a phase shifter 110. Each of the phaseshifters 110 may be in the form of a delay line. The phase shifters 110are controlled by a computer C to introduce a certain amount of delay inthe corresponding transmission lines and thereby steer the beam fromboresight by an angle θ.

The transmitter TX generates the signal, which is applied to a corporatefeed 115, which splits the signal to be delivered to each of theradiating elements 105. Prior to reaching the radiating element, thesignal from the feed passes through the corresponding phase shifter 110such that the phase of the signal in each delay line is changed by anindividual amount to cause the beam to steer. The phase shifters 110 canalso be controlled by an on-chip processor or baseband processor. Therange of each phase shifter can be quantized into a look-up table (LUT).The beam can be steered by quickly retrieving a phase value from thememory. The reverse happens for reception.

The example illustrated in FIG. 1 is a passive phased array or passiveelectronically scanned array (PESA), which is a phased array in whichthe antenna elements are connected to a single transmitter and/orreceiver. However, the disclosed embodiments are not limited to PESA,but rather encompass any electronically steerable antenna. For example,an active phased array or active electronically scanned array (AESA) mayalso be used. AESA is a phased array in which each antenna element hasan analog transmitter/receiver (T/R) module which creates the phaseshifting required to electronically steer the antenna beam. Any of thedisclosed embodiments may also be implemented using a digital beamforming (DBF) phased array, which has a digital receiver/exciter at eachelement in the array. The signal at each element is digitized by thereceiver/exciter, so that antenna beams can be formed digitally in afield programmable gate array (FPGA) or the array computer 110. Thisapproach allows for multiple simultaneous antenna beams to be formed,e.g., by grouping the radiating elements into sub-groups.

Also, the subject assignee has developed a phase array antenna whereinthe phase shifters are formed using delay lines that traverse variabledielectric constant material, such as, e.g., liquid crystals. Suchphased array antenna is also suitable for embodiments disclosed herein.Examples of such arrays are described in, e.g., U.S. Pat. No. 7,884,766;and published applications US2017/0093363; US2018/0159213; andUS2018/0062272; the content of which is incorporated herein in theirentirety by reference.

In general, it should be appreciated that for each of the disclosedembodiments, each antenna is any electronically steerable antenna havingplurality of radiators, such as the phased array antenna similar to theexample illustrated in FIG. 1. For simplicity, the disclosure providedherein uses the term “phased array antenna”, but it should beappreciated that the term encompasses any electronically steerableantenna having plurality of radiators forming a radiation pattern thedirection of which can be steered electronically.

FIG. 2 illustrates an embodiment for deployment of multiple phased arrayantennas for communication with one or more satellites. The arrangementof FIG. 2 enables continuous, in real time, reconfiguration of themultiple phased array antennas. In FIG. 2, asset 200 may be any platformhaving multiple communication devices, such as computers 1-n, thatcommunicate with one or more satellites 1-4. The asset 200 may be, e.g.,an airplane, a ship, a train, or a land based installation.

The asset includes a plurality of antennas ESA1-ESAn, that are coupledto a plurality of modems MD1-MDn via a switching mechanism 205. Each ofthe antennas has a phased array having its beam shape and directioncontrolled by phase controller 220. The phase controller 220 sets thephase or time delay of the signal for each of the radiators of thephased array to form the required main beam pointing at the desireddirection. The term phase controller is used herein as shorthand toindicate any controller used to electronically steer the beam formed bythe radiators. For example, the phase controller 220 may control thetime delay of the single-source RF signal as it is applied to each ofthe radiators. In another example, the phase controller 220 may be afield programmable gate array digitally forming the antenna beam.

In some embodiments the phase controller 220 may maintain a database,e.g., a lookup table, listing all of the available satellites and theirlocation in the sky. In some embodiments the phase controller 220 mayreceive GPS coordinates and other motion data of asset 200 from motioncircuitry 225 so as to be able to determine which satellites are withinthe field of view of its phased array. The phase controller 220 may usethis information to steer the beam of each phased array to theappropriate direction towards the satellites.

In some embodiments, the phase controller 220 includes a control portwhich receives a control signal from the control circuit 215 indicatingwith which satellite the antenna is to communicate with. The controlcircuit 215 may include a data port that is in functional connectionwith the router 210, so that the control circuit can actively base itsswitching decisions based on data collected from the router 210. Thedata may include bandwidth available for each antenna, data transmissionrate for each antenna, type of transmission required by eachcommunication device 1-n (voice, video, data, etc.).

The control circuit may also be connected to each of the ESA's andobtain RSSI signal from each of the EAS's. The control circuit mayfurther be connected to modem 255 and receive other data relevant to itsswitching decision, e.g., service level assigned to each communicationdevice, cost of transmission for each satellite, etc. For example, themodem 255 may be coupled to an external data and management system 260which is providing data to the control circuit 215 regarding varioustransmission parameters and users' accounts.

Using its database the phase controller calculates the phase delayapplied to each signal of each of the radiators so as to point theantenna in the direction of the indicated satellite. When the asset 200is a mobile unit, e.g., an airplane, a boat, etc., the motion circuitry225 continuously sends motion signals to the phase controller 220 sothat the phase controller can continuously adjust the phase applied toeach radiator so as to keep steering the beam towards the satellite.

The plurality of communication devices, here shown as computers 1-n, iscoupled to the modems MD1-MDn via the router 210. This arrangementenables real-time configuration of the system, such that anycommunication device 1-n can be coupled to any of the modems MD1-MDn,which can be coupled to any of the antennas ESA1-ESAn. This enablesefficient utilization of the bandwidth available from the satellites.

The multiple users on the platform may have varying needs, e.g., perhapsone computer is for crew welfare watching Netflix, while another ismanaging the ship's navigation. The control circuit 215 can determinewhich satellites to send the respective traffic over, and which antennaor antennas to use for that specific communication. The control circuit215 could also command the router 210 to aggregate the capacity orperform other Ethernet level operations on the traffic to ensure thehighest quality, best performance and lowest cost across all theavailable paths.

For example, in some embodiments the control circuit 215 receives dataregarding the bandwidth capacity and utilization of various satellites,data regarding the transmission priorities, e.g., live signal such asvoice or video calls must have high priority, while email can beallocated low priority, data regarding bandwidth cost of variousservices available on the satellites, etc. The control circuit 215 canthen determine which satellite should be used for which transmission.Also, in some embodiments the control circuit receives the motion signalfrom the motion circuitry 225, so that the control circuit 215 candetermine which satellites may be available for which antenna. In someembodiments the control circuit 215 also stores in its database thephysical configuration of asset 200 and its antennas. For example, theasset may have ESA1 on its right side, ESA2 on its left side, ESA 3 onthe roof, etc. From this the control circuit 215 may determine whichpart of the sky each antenna may be able to scan. Using all thisinformation, the control circuit 215 can provide the appropriate signalsto the switch and router to make the proper connections, and to indicateto each phase controller where to aim the antenna at.

To illustrate, FIG. 2 shows that both antennas ESA1 and ESA2 communicatewith Sat1, which in turn communicates with transceiver 1. So, in oneexample, the signal from Sat1 is too weak to send the required file overa single connection, the file can be sent over two connections usingreceive diversity combining methodology over ESA1 and ESA2 as onepossible solution. ESA3 communicates with Sat3, which in turncommunicates with transceiver 2. ESAn communicates with both satellitesSat2 and Sat4. Sat2 communicates with transceiver 2, while Sat4communicates with transceiver n. The two signals are routed by router230 to be combined by combining computer 235.

The example illustrated in FIG. 2 shows transceivers 1-3 being part of asingle base station 202 that is connected to a network 240, e.g., theInternet. Data storage 245 may be accessed via the network 240, or mayreside in the base station itself. Of course, many base stations may beemployed and the satellites may communicate with any selected basestation, depending on the user needs, the performance of each basestation, the connections available, etc. Also, since data storage 245may be accessed via the network 240, when a particular user machineneeds to access the data storage 245, the control circuit 215 maydetermine which satellite and which base station are best suited toserve that connection. Therefore, in some embodiments the controlcircuit 215 may periodically receive transmission with data regardingthe available base stations and their operational parameters. Similarly,for non-stationary satellites the control circuit 215 may periodicallyreceive transmission with updates regarding the satellites' location andoperational parameters.

Each of the transceivers of base station 202 has an antenna 204 thatexchanges communication signals with one or more satellites. Forcommunications with stationary satellites the antenna 204 may be asimple dish that is fixed in the direction of the satellite, or movedmechanically to steer it towards a desired satellite. However, forrapid, real-time steering, e.g., for non-stationary satellites or forfast moving between different satellites, one or more of antennas 204may be a phased array as disclosed herein.

In some disclosed embodiments, the satellites' transmission andreception is done via a unidirectional transmission mechanism. Forexample, the satellites' transmission and reception may employ the userdatagram protocol (UDP).

FIG. 3 illustrates an embodiment utilizing fiber optics for fast andefficient management of the multiple signals. Each of the phased arrayantennas includes an electro-optical transceiver EOT1-EOTn to convertbetween light signals and electrical signals. The optical signal travelsin optical fibers, illustrated in dash-line arrows, that are managed byoptical fiber management unit (OFMU) 320. The OFMU 320 also includes anelectro-optical modulator that converts between optical and electricalsignals. The signals traveling between the OFMU 320 and the switch 205are electrical, and travel in wave guides, coaxial cables, etc., whichis shown in solid-line arrows.

With the illustrated example of FIG. 3, the OFMU 320 can connect anyphased array antenna 1-n to any modem MD1-MDn via switch 205. Also, theoptical fiber management unit 320 can sum the RF signal from multipleselected phased array antennas and present the summed RF signal to aselected modem. Conversely, the optical fiber management unit 320 maysum the transmit power to multiple selected antennas for transmission.Furthermore, the OFMU 320 can perform other digital baseband operationsto create nulling, beam forming, or interference cancellation.

FIG. 3A illustrates a modification of the embodiment of FIG. 3, whereinthe optical fiber management unit 320 additionally performs thefunctions previously performed by switch 205. Since the fiber opticsmanagement unit 320 is capable of combining and splitting signals, itcan direct the signals to any of the modulators MD1-MDn, thus obviatingthe need for switch 205. The control circuit 215 then sends itsinstructions signals to the OFMU 320 to make the proper signal routing.

FIG. 4 illustrates an example of generating path diversity which isbeneficial especially for secure transmission of files or for loadbalancing. In the example illustrated in FIG. 4, platform 400, which maybe any of the platforms described herein having one or more phased arrayantenna(s), includes a computer 411 and is attempting to send a file F.In some examples, the data in the file is sensitive and it is desirableto frustrate a man-in-the-middle attack, such that even if it issuccessful, the perpetrator would only get part of the data. In otherexamples, it may be determined that the file is too large for thedetected RSSI so that it is desirable to use more than one path, whereineach path carries only part of the file.

As illustrated in FIG. 4, computer 411 splits file F into several, herethree parts. The control system 415 then operates the switch and router(see FIG. 1) to create three transmission paths, each directed at onesatellite. In the example illustrated in FIG. 4, each satellitecommunicates with a different base station, such that each part of thefile is received by a different antenna and transceiver system. This isnot always necessarily the case, as some or all of the satellites may becommunicating with the same base station. Regardless, the control system415 indicates to the base stations via configurator CFG1-CFGn which fileto receive from which satellite, and indicates to the data center 422that when the parts of the files are received, they are to be assembledinto a single file, which may be assembled and stored at the data center422. Of course, any return response can be similarly split and sent overmultiple paths.

Note that in the example of FIG. 4 the control system 415 is residing inthe cloud and not on the platform 400. Such an arrangement is notlimited to this particular example, but may be employed in any of theembodiment disclosed herein.

FIG. 5 is a flow chart illustrating non-ordered steps that may be takenin a process implemented by disclosed embodiments. For example, in step500 account data for registered users is loaded onto the control circuit215. The account data may include data speeds, data rate prices, datalimits, etc. The account data may be stored in the memory of the controlcircuitry. In step 505 satellite data may be loaded onto the controlcircuit 215. The satellite data may include satellite ID, satellitecoordinates, transmission rate, bandwidth, etc. In step 510 motion datamay be uploaded onto the control circuit 215. The motion data mayinclude motion data relating to the satellites and motion data relatingto the platforms upon which the ESA's are mounted. Note that all of thedata uploaded in steps 500, 505 and 510 may be updated periodically.

In step 515 a transmission request is received from a user. Using theinformation in the transmission request, and the data uploaded in steps500, 505 and 510, in step 520 a proper path(s) is selected for thetransmission. For example, if multiple antennas are available, thetransmission can be performed over multiple paths using multipleantennas, e.g., employing the diversity combining methodology. In step525 the transmission/reception strength is verified for the antenna(s)in the path selected. This may be done by, e.g., receiving the RSSI fromeach unit. When the proper signal strength for the selected path isverified, the switch is set to connect the selected antenna(s) to theselected modem(s) and the router is set to connect the user's machine tothe selected modem(s).

FIG. 6 illustrates an example of an embodiment utilizing multipleantennas, e.g., multiple phased arrays, to improve the overall signal tonoise ratio (SNR) of the received signal. Utilizing multiple antennas toimprove the SNR of a received signal is known in the art, but currentimplementations are either inadequate or too complicated/expensive forwide implementation. For example, the simplest implementation is todetermine which antenna provides the strongest total instantaneoussignal (e.g., highest RSSI) and select that antenna's signal. Anotherfast method is to simply apply equal weight to each antenna and sum upthe weighted signals from all of the antennas. While such an approach isfast and easy to implement, it loses signal quality of the best antennaand may weight a weak signal too highly, thereby introducing noise. Forfurther information the reader is directed to D. R. Pauluzzi and N. C.Beaulieu, “A comparison of SNR estimation techniques for the AWGNchannel” IEEE https://ieeexplore.ieee.org/document/871393. Transactionson Wireless Communications, Vol. 48, No. 10, October 2000. Available at:The embodiment of FIG. 6 provides an improved weighting using a novelapproach that is fast and relatively simple to implement.

The architecture illustrated in FIG. 6 is referred to as DistributedElectronically Steerable Arrays (DESA), and since in the example of FIG.6 the multiple arrays are used to combine a diversity received signal,it may be referred to as receive diversity combining architecture forDESA. Such an architecture is especially beneficial when one or more ofthe arrays do not have clear view of the satellite or due to the beamtilt angle have a very small aperture. This is exemplified in FIG. 6 byconsidering a mobile platform 600, such as a ship, wherein the antennasare positioned in different sections of the ship. The ship may betraveling in a direction wherein the satellite is on its starboard, suchthat arrays x₁, x₂ and x₃ (x₃ not shown, e.g., on the stern), may have agood signal, but since x₄ is positioned on port side, it may not be ableto steer towards the satellite, or the angle of steering may cause avery small aperture, thus noisy signal.

Modem 602 conditions the signal for transmission, e.g., signal from theInternet, such as streaming video, etc. The signal is uploaded to thesatellite SAT1 from base station 604 and the satellite SAT1 broadcastsit down to earth. The signal may be picked up by some or all of theantennas x₁-x₄, each having an individual SNR due to a variety offactors such as propagation loss, weather dynamics, polarizationmismatch, interference, physical orientation of the array, etc. Thesignal from the arrays is then processed by the DESA processing unit 640to generate a digital signal that is provided to modem 648, which thentransmit the signal to the various user devices. The DESA processingunit 640 includes an RF transceiver 642 that receives and digitizes thesignals from the antennas, and a digital signal processor 644 thatdetermines the weights to apply to the signal from each of the antennas,and then sums the weighted signals. The DESA processing unit 640 alsoincludes Antenna Interface Module AIM 646, which is the controllerresponsible for steering, geolocation and system management of thephased-array antennas. AIM 646 may have the structure and provideoperations and functions similar to those described with respect tophase controller 220 of FIG. 2.

FIG. 7 illustrates an embodiment of the receive signal path that may beused for receive diversity combining architecture, such as illustratedin the example of FIG. 6. The example of FIG. 7 includes as manychannels as antennas, wherein only the first and last channels areillustrated in details, while the rest are indicated by ellipses as theyare all identical. The disclosed approach is frequency band agnostic, soit can be applied to any frequency band. Each antenna receives thesatellite signal and, to illustrate, in this example the transmission isin the Ka or Ku band. The signal passes through an RF filter and is thenapplied to a standard Low Noise Block (LNB) which down-converts thesignal to an intermediate frequency, which is in the L-band. After thesignal passes the intermediate frequency filter, it is amplified andconverted into a digital signal by the RF ADC converter. The digitalsignal processor DSP 644 then applies a calculated weight to eachchannel and sums the signals from all of the channels.

FIG. 8 illustrates an example of a digital signal processor that may beemployed to support the receive diversity combining architectureaccording to embodiments disclosed herein. Due to path differences andother atmospheric effects, the signal of the channels needs to besynchronized and calibrated to match each other. In the embodiment ofFIG. 8 this is done by the channel scanner 850 first determining thechannel of highest fidelity by comparing each channel's correlation withthe rest of channels. In essence, channel scanner examines the channelsto select the most trustworthy channel as the golden reference channel.The golden reference channel is used by the time synchronizer 860 toestimate the time shift required to time-align all the channels. In oneexample, for each receive channel Rx_(N) the time synchronizer 860up-samples the signals to achieve desired fractional-sample accuracy. Itthen determines the cross correlation of the receive channel with thegolden reference channel. It then sets the maximum coefficient value asthe path delay difference and uses it to align the receive channelRx_(N) to the golden reference sample.

Similarly, the golden reference channel is used by the phase calibrationmodule 862 to estimate the phase shift required to align all thechannels. In one example, for each receive channel Rx_(N) the phasecalibration module 862 calculates the mean value of the phase differencebetween the receive channel Rx_(N) and the golden reference channel. Itthen applies the mean phase error value to the receive channel Rx_(N).

As noted, the channel scanner 850 ranks the channels according to theirrelative fidelity or trust worthiness. This is done by first deriving across correlation matrix by the cross correlation module 854. Theresults of the cross correlation are used by the ranking module 856 togenerate a rank order of the channels, which is referred to herein aslevel 1 ranking, and to select the golden reference channel. The level 1signal is provided to the rank controller 870.

In this respect, the cross correlation matrix is derived as:

${CC_{m,n}} = {\max \left\{ {{\frac{1}{ns}{\sum\limits_{\tau}^{nd}{\sum\limits_{t}^{ns}{{x_{m}\lbrack t\rbrack} \cdot {x_{n}\left\lbrack {t - \tau} \right\rbrack}}}}}} \right\}}$

where m≠n, ns is the integration length, and nd is the delay searchwindow. For N-channel receiver, the expression generates d number ofcross correlation coefficients, where d=Σ₁ ^(N-1)i is an integer,according to the triangle of the square matrix below

For example, for N=4, the expression generates an array of Σ₁ ³i=6coefficients:

CC _(m,n)=[CC _(1,2) ,CC _(1,3) ,CC _(1,4) ,CC _(2,3) ,CC _(2,4) ,CC_(3,4)]

The coefficients obtained from the matrix are used for level 1 rankingdetermination. A Q-matrix of dimension N by N−1 is defined, where eachchannel data is used exactly N−1 times from the correlation matrixcalculation. The correlation sum (CS) associated with each n-th channelis computed by adding all the row elements of Q as given by:

${CS}_{n} = {{\sum\limits_{i \neq n}{CC}_{n,i}} + {CC}_{i,n}}$

For the example of N=4 the expression is:

$\left. \begin{Bmatrix}x_{1} \\x_{2} \\x_{3} \\x_{4}\end{Bmatrix}\rightarrow Q \right. = {\left. \begin{bmatrix}{CC_{1,2}} & {CC}_{1,3} & {CC}_{1,4} \\{CC_{1,2}} & {CC}_{2,3} & {CC}_{2,4} \\{CC_{1,3}} & {CC}_{2,3} & {CC}_{3,4} \\{CC_{1,4}} & {CC}_{2,4} & {CC}_{3,4}\end{bmatrix}\rightarrow{CS} \right. = {\begin{bmatrix}{{CC}_{1,2} + {CC}_{1,3} + {CC}_{1,4}} \\{{CC}_{1,2} + {CC}_{2,3} + {CC}_{2,4}} \\{{CC}_{1,3} + {CC}_{2,3} + {CC}_{3,4}} \\{{CC}_{1,4} + {CC}_{2,4} + {CC}_{3,4}}\end{bmatrix} = \begin{bmatrix}{CS}_{1} \\{CS}_{2} \\{CS}_{3} \\{CS}_{4}\end{bmatrix}}}$

The golden reference channel is selected based on the highest score asdefined in the set:

${SCORE} = {{\phi_{CS}\left( \frac{CS}{\sum_{i}{CS_{i}}} \right)}^{N} = {\quad{\left\lbrack {{SCORE}_{1},\ldots \mspace{11mu},\ {SCORE}_{N}} \right\rbrack = {\quad\left\lbrack {{\phi_{CS}\left( \frac{CS_{1}}{\sum_{i}{CS_{i}}} \right)}^{N},{\ldots \mspace{9mu} \left( {,\ \phi} \right)_{CS}\left( \frac{CS_{N}}{\sum_{i}{CS_{i}}} \right)^{N}}} \right\rbrack}}}}$

where φ is a gain function comprised of a normalizer and scaler. In thecase of a tied score, it is possible to select one of the tied channels,or, in this embodiment use the results of the level 2 rankingdetermination to select the golden reference channel for higheraccuracy.

Referring back to FIG. 8, the channel scanner 850 includes a peak toaverage power module 852, which calculates the level 2 ranking based onpeak to average power ratio (PAPR). The level 2 signal is applied to therank controller 870, which uses the level 1 and level 2 determinationsto generate the scores for the channels. The scores are provided to theweighting module 864 which applies the weights assigned to each channel,and then the weighted signal of all the channels is combined bydiversity combiner 866. Incidentally, as shown by the example of FIG. 8,an optional external input port is provided, enabling a user to overridethe rank controller's selection or provide other commands to the rankcontroller 870.

The level 2 ranking determination is based on calculating PAPR, usingthe expression:

${PAPR} = \frac{\max \left\{ {x}^{2} \right\}}{\frac{1}{K}{\sum\limits_{i = 1}^{K}{x_{i}\overset{¯}{x_{i}}}}}$

In this example the peak power is less than 1005 of maximum amplitudesquared, e.g., max{|x|²} corresponds to 99% PAPR in a collection windowof K samples. Using 99% PAPR avoids unrealistic peaks due to systemerror, glitch or sampling error. While this particular example uses 99%,any other value may be used that is less than 100%. Higher PAPR impliesworse radiowave propagation channel and reduced Eb/N0 (energy per bit tonoise power spectral density ratio—a normalized signal-to-noise ratio(SNR) measure, also known as the “SNR per bit”).

Ideally, level 1 max(CS) and level 2 min(PAPR) should correspond to thesame receive channel. The reference channel selection can be computed byjoint scores:

${SCORE}_{n} = \left( {{\phi_{CS}\left( \frac{CS_{n}}{\sum_{i}{CS_{i}}} \right)} \cdot {\phi_{PAPR}\left( \frac{\sum_{i}{PAPR_{i}}}{PAPR_{n}} \right)}} \right)^{N}$

Generally a scoring method may employ several decision variables basedon multiple physical quantities. As indicated above, the example of FIG.8 utilizes a cross correlation sum as level 1 ranking and PAPR as level2 ranking. By having another decision variable, PAPR, we can betterapproximate the true channel SNR, and hence closer to the optimalcombining solution. Additionally, other variables may be used, e.g.,total signal-plus-noise power (Psig). Therefore, a generalizeddescription of determining the n-th channel score for N multiple Rxchannels can be expressed as:

where SCORE=[SCORE₁, SCORE₂, . . . , SCORE_(N)] is an array of dimensionN, Q is the total number of decision variable, φ is the gain functionfor normalization, and θ is a scalar function. Ideally, level 1 max(CS)and level 2 min(PAPR) should correspond to the same receive channel. Thereference channel selection can be computed by joint scores for a betterapproximation of true channel condition:

${SCORE}_{n} = \left( {{\phi_{CS}\left( \frac{CS_{n}}{\sum_{i}{CS_{i}}} \right)} \cdot {\phi_{PAPR}\left( \frac{\sum_{i}{PAPR_{i}}}{PAPR_{n}} \right)}} \right)^{N}$

where n is the channel number that gives the highest score.

For the example given in FIG. 8, where Q=2 (level 1 ranking and level 2ranking) and N=4 channels, the expression for obtaining the scores is:

${SCORE} = {\left( {{\phi_{1}\left( \theta_{1} \right)} \cdot {\phi_{2}\left( \theta_{2} \right)}} \right)^{4} = \left( {{\phi \left( \frac{CS}{\sum_{i}{CS_{i}}} \right)} \cdot {\phi \left( \frac{\sum_{i}{PAPR_{i}}}{PAPR} \right)}} \right)^{4}}$

which is the value used in the weighting coefficients of weightingmodule 864. Channels with better condition and higher quality will beweighted exponentially more, presenting a higher SNR at the output ofthe diversity combiner 866.

Also shown in FIG. 8 is the monitoring port leading to controller 870.In this embodiment, controller 870 monitors the output of the diversitycombiner 866 and determines the noise variance of the output. This maybe done, for example, by using the same PAPR process described above.The controller 870 may compare the PAPR determined for the diversitycombined signal with respect to the PAPR calculated for each of theincoming signal. This is done so that the controller 870 monitors thatthe signal generated after the diversity combining has indeed lower PAPRand, if not, the weights may need to be varied to achieve a reduction inthe PAPR of the diversity combined signal.

With the provided disclosure, a method for combining a transmissionsignals received at a plurality of antennas is disclosed, comprising:calculating a cross correlation coefficient for signals obtained fromeach of the plurality of antennas; selecting the signal generating thehighest coefficient as a golden reference signal; using the goldenreference signal to time-synchronize the transmission signals receivedat a plurality of antennas; deriving peak power to average power ratiofor each of the transmission signals received at a plurality ofantennas; using the cross correlation coefficients and the peak power toaverage power ratio to generate a weighting coefficient for each of thetransmission signals received at a plurality of antennas; applying theweighting coefficient to each of the transmission signals received at aplurality of antennas to generate a plurality of weighted signals; andsumming the plurality of weighted signals. As noted, the method mayfurther include using the golden reference signal to calibrate the phaseof the transmission signals received at a plurality of antennas.

A system is provided for receiving a transmission signal, comprising: aplurality of antennas, each antenna receiving a received signal; aranking module ranking the plurality of antennas according to quality ofthe received signal of each of the plurality of antennas and generatinga corresponding level one signal, and selecting highest ranking antennaas a golden reference signal; a synchronizer using the golden referencesignal to synchronize the received signals of all of the plurality ofantennas; a level two module calculating peak to average power ratio foreach of the received signal of each of the plurality of antennas andgenerating a corresponding level two signal; a scoring unit generating aweighting score for each of the received signal of each of the pluralityof antennas using the level one and level two signals; a weightingmodule applying the weighting score to each corresponding receivedsignal of each of the plurality of antennas to generate a plurality ofweighted signals; and, a summing module combining all of the weightedsignals.

FIG. 2A illustrates an embodiment for satellite communicationimplementing receive diversity combing for improve overall SNR. Theembodiment of FIG. 2A is similar to the embodiment illustrated in FIG.2, and therefore will not be described in details. The embodiment inFIG. 2A illustrates how the DESA elements of FIGS. 7 and 8 can beincorporated into the architecture of FIG. 2, thus enabling receivediversity combing for improve overall SNR.

Similarly, FIG. 3B illustrates an embodiment for satellite communicationimplementing receive diversity combing to improve the overall SNR, whichincorporates fiber optics. The embodiment of FIG. 3B is similar to theembodiment illustrated in FIG. 3, and therefore will not be described indetails. The embodiment in FIG. 3B illustrates how the DESA elements ofFIGS. 7 and 8 can be incorporated into the architecture of FIG. 3, thusenabling receive diversity combing for improve overall SNR.

FIG. 5A illustrates a flow chart for non-ordered steps of an embodimentthat may be taken to perform diversity receive combine operation forimproved overall SNR. In step 540 the signal is received at multipleantennas, which may include, e.g., cellular antennas, Wi-Fi antennas,array antennas, etc. While the data of the signal received at theantennas is the same, the quality of the signal received at each antennamay not be the same, thus causing different SNR or RSSI at each channel.The method proceeds to generate a weighted sum of the signals so as toimprove the overall SNR, as follows. The method generates two rankingsignals, a level one ranking signal and a level two ranking signal. Thelevel one ranking signal is generated in step 545 by obtainingcoefficients of cross correlations of the signals from the multiplechannels. The ranking is ordered such that the highest coefficient isthe best signal and the lowest coefficient is the worst channel. Also,at step 550 the best channel (highest coefficient) is selected as thegolden reference signal. The level two ranking signal is generated instep 555, by calculating the PAPR for each of the channels. The rankingis ordered such that the lowest PAPR is the best signal and the highestPAPR is the worst channel.

At step 560 the golden reference signal is used to synchronize thechannels in time domain. At step 565 the golden reference signal is usedto calibrate the phase of all the channels. At step 570 the level oneranking and the level two ranking are used to generate weights and thenthe signal of each channel is weighted by the corresponding weight. Atstep 575 the weighted signals of the channels are added together.

It should be understood that processes and techniques described hereinare not inherently related to any particular apparatus and may beimplemented by any suitable combination of components. Further, varioustypes of general purpose devices may be used in accordance with theteachings described herein. The present invention has been described inrelation to particular examples, which are intended in all respects tobe illustrative rather than restrictive. Those skilled in the art willappreciate that many different combinations will be suitable forpracticing the present invention.

Moreover, other implementations of the invention will be apparent tothose skilled in the art from consideration of the specification andpractice of the invention disclosed herein. Various aspects and/orcomponents of the described embodiments may be used singly or in anycombination. It is intended that the specification and examples beconsidered as exemplary only, with a true scope and spirit of theinvention being indicated by the following claims.

1. A method for combining received signals from a plurality of antennas,comprising: for each of the antennas generating a ranking scoreindicative of trust worthiness of the received signal; for each of theantennas generating a quality score indicative of the peak to averagepower ratio (PAPR) of the received signal; for each of the antennasusing the corresponding ranking score and quality score to generate aweight; for each of the antennas applying the weight to the receivedsignal to generate weighted signal; and, summing all weighted signalsfrom the plurality of antennas to generate a weighted combined signal.2. The method of claim 1, wherein generating a ranking score comprisescalculating cross correlation coefficient.
 3. The method of claim 2,wherein calculating cross correlation coefficient comprises for each twoantennas m and n, calculating the coefficient CC_(m,n) by theexpression:${CC_{m,n}} = {\max {\left\{ {{\frac{1}{ns}{\sum\limits_{\tau}^{nd}{\sum\limits_{t}^{ns}{\overset{\_}{x_{m}\lbrack t\rbrack} \cdot {x_{n}\left\lbrack {t - \tau} \right\rbrack}}}}}} \right\}.}}$wherein m≠n, ns is integration length, nd is delay search window,x_(m)[t] is average signal intensity of channel m over the integrationlength and x_(n)[t−τ] is instantaneous intensity value of channel n attime r shift within the integration length.
 4. The method of claim 3,wherein generating a ranking score further comprises calculatingcorrelation sum CS_(n) for each antenna n by:${CS}_{n} = {{\sum\limits_{i \neq n}{CC}_{n,i}} + {CC}_{i,n}}$
 5. Themethod of claim 4, wherein generating a ranking score further comprisescalculating a score for each antenna n as:${{SCOR}E_{n}} = {\phi_{CS}\left( \frac{{CS}_{n}}{\Sigma_{i}CS_{i}} \right)}$where φ is a gain function comprised of a normalizer and scaler.
 6. Themethod of claim 1, further comprising assigning received signal havinghighest ranking score as reference signal and time-aligning all receivedsignals to the reference signal.
 7. The method of claim 1, furthercomprising assigning received signal having highest ranking score asreference signal and calibrating phase of all received signals to thereference signal.
 8. The method of claim 1, further comprising:assigning received signal having highest ranking score and lowestquality score as reference signal; time-aligning all received signals tothe reference signal; and, calibrating phase of all received signals tothe reference signal.
 9. The method of claim 1, wherein generating thequality score comprises calculating the PAPR using a numerator valuewhich is below 100% of maximum amplitude squared.
 10. The method ofclaim 1, wherein generating the quality score comprises calculating thePAPR using a numerator value which is 99% of maximum amplitude squared.11. A method for combining received signals from a plurality ofantennas, comprising: calculating a cross correlation coefficient forthe received signals obtained from each of the plurality of antennas;selecting a signal generating the highest coefficient as a goldenreference signal; using the golden reference signal to time-synchronizethe received signals; deriving peak power to average power ratio (PAPR)for each of the received signals; using the cross correlationcoefficients and the peak power to average power ratio to generate aweighting coefficient for each of the received signals; applying theweighting coefficient to each of the received signals to generate aplurality of weighted signals; and, summing the plurality of weightedsignals.
 12. The method of claim 11, further comprising using the goldenreference signal to calibrate the phase of the received signals.
 13. Themethod of claim 11, wherein deriving PAPR further comprises calculatingcorrelation sum CS_(n) for each received signal.
 14. The method of claim11, wherein deriving PAPR comprises using a numerator value which isbelow 100% of maximum amplitude squared.
 15. A system for combiningreceived signals from a plurality of antennas, comprising: a signaldigitizer receiving the received signals and generating digitizedsignals; a first ranking module ranking the digitized signals bycomparing each of digitized signal's correlation with the rest of thedigitized signals and selecting highest ranked digitized signal as areference signal; a second ranking module calculating a peak to averagepower ratio (PAPR) for each digitized signal; a weighting modulereceiving the ranking from the first ranking module and the PAPR fromthe second ranking module and generating an assigned weight for each ofthe digitized signals; a weight applicator applying the assigned weightto each of the digitized signals to generate weighted signals; a summingmodule summing the weighted signals.
 16. The system of claim 15, furthercomprising a time synchronizer synchronizing the digital signalsaccording to the reference signal.
 17. The system of claim 15, furthercomprising a phase calibration module calibrating the digital signalsaccording to the reference signal.
 18. The system of claim 15, whereinthe first ranking module comprises a cross-correlation calculatingmodule.
 19. The system of claim 18, wherein the first ranking modulefurther comprises a correlation sum module summing cross-correlationcoefficients calculated by the cross-correlation calculating module. 20.The system of claim 15, wherein each of the antennas comprises anelectronically steerable array.